Method for obtaining products for the food industry and/or feed industry from insects, and solid phase obtained from insects

ABSTRACT

A method for obtaining products for the food industry and/or feed industry from insects at the larval stage involves: a) comminuting the insects to form an insect pulp; b) shifting the pH-value of the insect pulp to an acid range by adding an acid and malaxing the insect pulp for a period of at least 45 minutes; and c) fractioning the insect pulp using centrifugal treatment into at least two fractions i) a solid fraction, ii) a fatty phase; and a fat-reduced solid phase.

BACKGROUND AND SUMMARY OF THE INVENTION

Exemplary embodiments of the present invention relate to a method for obtaining products of the food industry and/or feed industry from insects.

Furthermore, exemplary embodiments of the present invention relate to a low-fat and thus particularly high-protein solid phase obtained from insects. The fatty phase can also be called oil phase or oil fraction.

The fractioning of the pulp from insect larvae is currently carried out sporadically on an industrial scale. The few companies that produce today use a method with the addition of water. Alternatively, presses are also used, whereby the fat can be pressed off the solids together with the water. If insect larvae are dried beforehand, the oil can be pressed off the solids.

In contrast to the use of presses, the aqueous process allows a solid to be obtained that has a high protein content and a lower residual fat content. The solid can be used as animal feed or for use as food. Low residual fat values are advantageous for further processing, packaging and storage.

WO 201 3/1 91 548 A1, in the field of fractioning of insects, describes a process involving the crushing of insects and worms to a pulp, especially to a particle size of 1 mm. This is followed by enzymatic hydrolysis at 35-65° C. with acidic protease at pH 3-6 or a neutral protease at pH 6-8. The pulp is then heated to temperatures of 70-100° C. and finally separated in three phases to form an oil fraction, an aqueous protein fraction, and a solids fraction. The fractions can then be dried.

Furthermore, WO 2014/123420 A1 discloses a fractioning processing involving the following process sequence. A comminution of insects and/or worms, especially insect larvae, into a pulp, wherein the comminution is carried out to a mean particle size of less than 1 mm. The insect pulp is then heated to 70-100° C. Finally, the method comprises a separation into three phases, an oil fraction, an aqueous protein fraction, and a solids-containing fraction. The method is enzyme-free and includes drying of individual products. Killing of insects or worms is not disclosed in this publication. When processing worms and insects according to the method described in this publication, it has been shown that within a very short time after crushing, a brown discoloration of the insect pulp occurs. This effect is also described below as the “Browning Effect”. This effect influences the feed quality and customer acceptance of the product.

WO 2015/070194 A1 discloses a method for recovering dried insect pulp from which chitin has previously been separated. This can be carried out by filtration or alternatively by centrifugal treatment. According to the process of WO 2015/070194 A1, the whole insect is crushed, the insect pulp is then treated, including the separation of chitin and finally the remaining insect pulp is evaporated to a solid (see e.g., FIG. 1). According to p.14 line 21, it may be necessary to heat the drying residue again for a certain time to kill microbes or similar.

WO 2017/066880 A1 discloses a method for processing insects. In the disclosed method, FIGS. 2A, 2B, 2C, 3A, 3B, 4A, 4B each use “at least one frozen washed insect or freeze-dried insect” as the starting product. FIG. 1 shows under “prior art” the form of killing. In step 2, at least one living insect is used and in step 4 “freezing and storage”. It is common knowledge that most insects do not survive freezing. Therefore, according to the process of WO 2017/066880 A1 the killing is carried out by freezing.

WO 2018/122294 A1 discloses a method for processing a biomass with simultaneous extraction of proteins and lipids from insects. Exemplary embodiments involve killing the insects by freeze-drying. A strategy for the processing of the biomass is pursued, which includes a separation into a fat and a water phase. The water phase may also contain, inter alia, insoluble components (solids). A separate solid phase is not separated.

It has been shown that the methods described above are either comparatively expensive and labor-intensive or only allow inadequate degreasing of the solid fraction, which prevents good further processing.

Therefore, exemplary embodiments of the present invention are directed to further optimizing the processing of insect pulp.

A method according to the invention is used to obtain products of the food industry and/or feed industry from insects, in particular from insects in the larval stage. It is characterized by the following steps:

-   -   a) Comminuting the insects to form an insect pulp;     -   b) Shifting the pH value of the insect pulp to an acidic range         by adding an acid and malaxing the insect pulp for at least 45         minutes; and     -   c) Fractioning the insect pulp into at least two fractions         -   i) a solid fraction,         -   ii) a fatty phase

The fatty phase can also be described as an oil fraction. The solid fraction may contain protein. Alternatively, an additional third aqueous protein fraction can also be obtained, which can then be dried, e.g., by an evaporator, so that the water obtained is recyclable in the process and that the protein obtained represents a separate valuable material phase.

The protein-containing solid fraction can be used as animal feed.

Preferably, the solid fraction can be ground and/or dried in further method steps.

In this context, the prior separation of fat or oil is of particular importance, as otherwise further comminution in the subsequent method steps is either impossible or very difficult. Lubrication occurs, which makes processing in a feed mill, for example, almost impossible.

Furthermore, the low fat content also allows the addition of one or more foreign fats and/or oils, i.e., fats and/or oils that are not contained in the originally used insects, which increases the variance in the formulation. Thus, for example, essential oils and/or fats can be added.

The products of the food industry and/or feed industry include animal feed but also sports nutrition.

The oil fraction or fat fraction can be used as a separate valuable material phase, preferably as fuel and/or animal feed.

Tests have surprisingly shown that the combination of malaxation, in particular mixing and/or kneading, over the minimum period of time described above with additional acid addition allows a much better separation efficiency of the fat or oil from the solid (more than 20% higher) than the procedure of WO 2014/123420 A1.

In particular, the method according to the invention can be carried out without the additional supply of enzymes, which makes the process particularly economical by omitting the usually expensive enzymes and also particularly efficient, since enzyme separation and/or recovery becomes unnecessary.

The fractioning of the insect pulp into three phases can be carried out in one or more stages. A single-stage fractioning can be carried out in a 3-phase decanter, for example. A multi-stage fractioning can be carried out in such a way that two centrifugal separation steps are carried out one after the other, wherein both decanters and separators can be used for the separation steps.

The solid fraction can then be subjected to drying.

Acid addition can be carried out advantageously within less than 10 minutes, especially preferably within less than 5 minutes, after comminution, so that side reactions or rearrangements, such as protein folding and/or oxidative effects, are advantageously avoided before acid addition.

The pH value of the insect pulp after the addition of the acid less than pH=6.5 can preferably be in the range of pH=2 to pH=4.5, especially preferably between pH=2 to pH=3. Especially in these pH ranges, a particularly effective separation of the oil phase was observed.

The temperature during malaxation and/or fractioning can be at least 60° C., preferably 80-100° C., especially 85-95° C. At this temperature a particularly good centrifugal separation of the oil phase is achieved.

Malaxing can be performed advantageously at least over a period of 55 minutes, preferably 60-130 minutes, and especially preferably 90-120 minutes.

The fatty phase obtained by fractioning can be processed by fat polishing, e.g., by using a separating separator, in order to obtain an oil phase of particularly high purity.

The average particle size of the insect parts in the insect pulp after crushing can be advantageously smaller than 2 mm, especially between 1 and 2 mm.

The acid can advantageously be a diluted hydrochloric acid, preferably a hydrochloric acid with a concentration of 0.001 mol/L to 0.5 mol/L. Chlorides are predominantly highly soluble in water, so that certain salts can be separated from the solid with the water phase.

After fractioning, it is advantageous to neutralize the fraction by adding a base, in particular by adding a diluted NaOH solution, for better compatibility of the solid phase when used as food or feed.

Before the insects are comminuted, the insects are killed for better process control.

After killing the insects and before comminuting the insects, the insects can be cleaned. This can preferably be carried out by washing, especially by a superficial wash.

Water can be added during malaxation and/or fractioning to adjust the viscosity for transfer and the separation efficiency.

Fractioning can take place in at least one decanter, in particular in a 3-phase decanter, a 2-phase decanter and a separator, and/or a 2-phase decanter.

Furthermore, a solid phase obtained from insects with a residual oil content of less than 15% by weight, in particular obtained by the method according to the invention, is described. The solid phase is obtained from insects and therefore, unlike plants, contains chitin.

The protein content of the solid phase is relatively high. It amounts to more than 50 wt. %, preferably more than 90 wt. %, especially preferably more than 95 wt. %.

Unlike other animal protein sources such as pork, beef or chicken, the solid phase can be produced free of antibiotics and has a very favorable CO₂ balance due to processing and breeding.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

In the following, several variants of the method according to the invention are explained in detail and with the help of the enclosed figures. Individual details described in the following can also be taken as separate features in their own right, detached from the concrete exemplary embodiment, wherein:

FIG. 1 shows a basic process diagram of an exemplary embodiment of the method according to the invention;

FIG. 2 shows method details of a first variant of fractioning within the scope of the method according to the invention;

FIG. 3 shows method details of a second variant of fractioning within the scope of the method according to the invention;

FIG. 4 shows method details of a third variant of fractioning within the scope of the method according to the invention;

FIG. 5 shows a tabular representation of test results from the processing of flour beetle larvae according to the method according to the invention;

FIG. 6 shows a heat exchanger for killing insects.

DETAILED DESCRIPTION

Insects and, in particular, insect larvae are used as the starting material for protein extraction. Insect larvae of the Hermetia illucens (black soldier fly), the Ceratitis capitata (Mediterranean fruit fly), and/or the Tenebrio molitor (flour beetle) are particularly preferred. However, other insects and preferably their insects in the larval stage can be considered as well.

In a first method step 1 the insect larvae are killed. The killing can be done by treatment in a hot water bath.

In a second method step 2, the insect larvae can optionally be cleaned. This can be done by screening.

In a third method step 3, the insect larvae are comminuted into an insect pulp.

In this process, the larvae are comminuted (e.g., ground) to facilitate digestion by subsequent pH reduction. This can be carried out with a mill or press. The comminution can be advantageously carried out to a mean particle size <2 mm, in particular to a mean particle size or grain size between 1 and 2 mm. A meat grinder can be used for this purpose, for example. Smaller particle sizes may allow a better disintegration, but their production by e.g., rotating cutting units can promote the formation of an emulsion by breaking up the oil components, which in turn worsens the separation.

In a fourth method step 4, the insect pulp is heated and stirred. In addition, the pH value is lowered.

The insect pulp resulting from the comminution can be stirred under the influence of heat for a certain period of time, preferably up to 3 hours, and heated up and/or kept at temperature. The preferred temperature in this step is 60-100° C. This process is also called malaxation. The insect pulp can be treated in a malaxer in this step.

Malaxation can preferably be carried out over a period of 60-130 minutes, particularly preferably 90-120 minutes, and can also preferably be carried out simultaneously with or immediately after the addition of acid.

The temperature during malaxation is preferably in a range of 80-100° C., especially below the boiling point of water, i.e., preferably 85-95° C. This preferably serves to terminate the enzyme activity and thus prevents denaturation, since the mushy substance obtained from insects would otherwise quickly turn black on the surface.

The natural pH value of insect larvae is typically in the slightly alkaline range. This is approximately pH=8.0 for the larva of the black soldier fly and pH=7.3 for the Mediterranean fruit fly larva.

According to the invention, the pH-value of the insect pulp is lowered into the acidic range at pH=1.5 to 6.5 after comminution by adding an acid.

This is done by adding an acid 200 and optionally by adding water 100.

The addition of water 100 to the insect pulp depends on whether the insect pulp contains enough of its own liquid. If this is not the case, additional dilution water must be added to the malaxer and/or in a subsequent method step 5 of a fractioning by centrifuge.

Sufficient liquid is present when free liquid is visible under the oil phase in the insect pulp during a centrifugation test in the laboratory centrifuge.

The addition of acid starts immediately, preferably within less than 10 minutes, especially preferably within less than 5 minutes, after the comminution in method step 3.

The acid addition can preferably be completed within less than 5 minutes.

A strong inorganic acid can preferably be used as acid. This acid can be added as diluted acid in aqueous form, preferably as 1 molar acid or in even higher dilution, to avoid a selective overacidification of the insect pulp during acid addition and to avoid dissociation effects.

Hydrochloric acid HCl is the particularly preferred acid, preferably as HCl solution.

The preferred adjusted pH-value of the insect pulp after the addition of acid is pH=2 to pH=4.5. The preferred pH-value of the insect pulp is between pH=2 and pH=3.

In a fifth method step 5, the insect pulp is fractionated. The fractioning of insect larvae can be carried out by a separating device of the centrifugal separation technique.

The acidified and optionally malaxed insect pulp can now be separated into at least two fractions by means of a centrifuge, in particular a decanter centrifuge.

The decanter centrifuge can preferably be operated at least 3500 G. It has been shown that lower residual oil values in the solids can be achieved by prior malaxation and the addition of acid than without the pH value reduction and/or without malaxation.

The use of a decanter is preferred and particularly suitable for the separation of the solid phase. A 3-phase decanter or a 2-phase decanter can be used for this purpose.

During or after fractioning 5, a caustic solution 300 can be added as an option to neutralize individual fractions, preferably the solid phase and/or the water phase.

Variations of the fractioning of method step 5 are shown in FIGS. 2 to 4.

In method step 5, a single-stage fractioning 5-1 can be performed in a 3-phase decanter as shown in FIG. 2 by dividing the insect pulp into several fractions.

In this process, the insect pulp is divided into a fatty phase 600, a water phase 400 and a solid phase 500. The terms “phase” and “fraction” are to be understood synonymously in the context of the present invention.

In method step 5, a second fractioning 5-2 can be carried out in several stages in a 2-phase decanter as the first fractioning stage and a separator as the second fractioning stage as shown in FIG. 3.

In this process, the insect pulp is divided into a fatty aqueous phase 700 and a solid phase 500. The aqueous fatty phase 700 can then be divided in a separator into an aqueous phase 400 and a fatty phase 600.

Both the water phase 400 and the solid phase 500 may contain proteins of insect larvae. The proteins can be present, for example, as protein curd suspended in the water of the water phase 400.

In method step 5, a third fractioning 5-3 can also be carried out in a 2-phase decanter in several stages as shown in FIG. 4, followed by a subsequent treatment in an evaporator.

In this process, the insect pulp is divided into a fatty phase 600 and a solid-containing aqueous phase 800. From the aqueous solid-containing phase 800, a protein-rich solid phase 500 can then be produced by drying 8.

The degreasing of the solid material can be influenced by the setting of the separating device.

For this purpose, the fat content of the solid phase can optionally be measured and the speed and/or the differential speed of the decanter can be adjusted if the fat content of the solid phase exceeds a specified setpoint.

On the other hand, the way the insect pulp is produced has an influence on the separation result.

Surprisingly, a shift in the pH-value of the insect pulp shows a positive influence on the separation behavior, resulting in a particularly low residual fat content in the degreased solid (lower fat values).

Finally, in a sixth method step 6, the fractions can be further processed, e.g., by a drying step.

In FIG. 2, further processing 6 of the fatty phase 600 is carried out by fat polishing 9. This can be carried out in a separator.

The water phase 400 can be subjected to drying 7, especially in an evaporator.

The solid phase 500 obtained in fractioning 5 according to FIGS. 2 to 4 can be dried by a drying step 8, preferably in a spray and/or disk dryer or in a dry mill, in particular a so-called ultra-rotor mill.

FIG. 5 shows a table of a test result as evidence of the surprisingly better separation efficiency for the separation of fat from the remaining fractions due to the pre-treatment steps described above.

The results give the residual fat content (values related to dry matter) in the solid.

The parameters for the spin test shown in FIG. 5 were the following:

-   -   Acceleration=4800 g,     -   Spinning time=1 to 2 minutes,     -   Temperature of the insect pulp and spinner more than 60° C.,         max. 95° C.,     -   Starting material: flour beetle larvae (comminuted)

FIG. 5 shows the retention time in table form, which is the time the insect pulp remains in the malaxer.

Furthermore, the pH value of the insect pulp during the centrifugation test is listed in a table.

A reduction of the residual fat content of more than 25% compared to an insect pulp from meal beetle larvae without pH treatment and with only a shorter residence time in the malaxer can be seen.

Experiments have shown that the previous killing of insects in combination with the separation of solids leads to a significant reduction of the “browning effect”, i.e., the brown discoloration after comminution.

This was observed especially when heating, especially boiling, e.g., in a hot water bath. Unlike e.g., freezing of insects, heating can also be done in-line, i.e., without batch operation. This simplifies the process engineering application and allows a further automation of the processing compared to the freezing of the insects.

Alternatively, heating can also be carried out by using a pipe heat exchanger, as shown in FIG. 6. Here the insects are transported together with water through the tubular heat exchanger, heated and killed.

As a variant of heating for the purpose of killing off, a continuous or in-line process can be used, based on the feed material of the living insects. This is a particular advantage when heating compared to a much more complex freezing process.

The introduction of temperature prior to the comminution causes a deactivation of the insect's own enzymes right at the beginning of the process, which prevents or significantly weakens the discoloration of the comminuted insect mass (browning). This is an essential advantage for the later use of the solid fraction.

If a medium such as water is used, the insects or larvae are also washed in this step, which can result in an additional increase in product quality.

This is shown in FIG. 6. Here, water and live insects are fed through a pump 15 through a heat exchanger 16. The water can be preheated water, which is further heated inside the heat exchanger 16, e.g., a pipe heat exchanger. This leads to the killing of insects by heating or boiling, similar to a hot water bath.

The temperature of the water in which the insects are kept is more than 60° C., preferably 75-100° C., when killing them.

The dwell time in the heat exchanger until killing is completed depends on the flow rate of the insects, the water temperature reached and the performance of the heat exchanger. The time can be calculated or determined by experiments.

The killed uncrushed insects are then separated from the aqueous solution. This can preferably be done by screening. In FIG. 6, a screening device in the form of a vibrating screen 19 is provided for this purpose.

A collection tank 20 is arranged below the screening device 19, from the collection tank the liquid can be discharged with a pump 21 via a drain.

The heat exchanger 16 has a circuit for the supply of a heating medium, e.g., hot water, with which the water/insect mixture in the heat exchanger can be heated indirectly. This circuit has at least one pump 17 and a second heat exchanger 18, which can be operated e.g., with superheated steam. The killed uncrushed insects leave the screening device 19 and can be fed to a crushing device e.g. a shredder, a press or a mill.

The entire method, including killing, can be carried out in continuous process control so that side reactions of the biological product are largely prevented or at least reduced.

The end product thus has fewer impurities and does not have to be purified extensively.

Although the invention has been illustrated and described in detail by way of preferred embodiments, the invention is not limited by the examples disclosed, and other variations can be derived from these by the person skilled in the art without leaving the scope of the invention. It is therefore clear that there is a plurality of possible variations. It is also clear that embodiments stated by way of example are only really examples that are not to be seen as limiting the scope, application possibilities or configuration of the invention in any way. In fact, the preceding description and the description of the figures enable the person skilled in the art to implement the exemplary embodiments in concrete manner, wherein, with the knowledge of the disclosed inventive concept, the person skilled in the art is able to undertake various changes, for example, with regard to the functioning or arrangement of individual elements stated in an exemplary embodiment without leaving the scope of the invention, which is defined by the claims and their legal equivalents, such as further explanations in the description.

LIST OF REFERENCE NUMERALS

-   Method step 1 Killing -   Method step 2 Cleaning -   Method step 3 Comminuting -   Method step 4 Malaxing -   Method step 5 Fractioning -   5-1 First fractioning variant -   5-2 Second fractioning variant -   5-3 Third fractioning variant -   6 Further processing -   7 Drying -   8 Drying -   9 Grease polishing -   15 Pump -   16 Heat exchanger -   17 Pump -   18 Second heat exchanger -   19 Vibrating screen -   20 Collection tank -   21 Pump -   100 Water -   200 Acid -   300 Caustic solution -   400 Water phase -   500 Solid phase -   600 Fatty phase -   700 Aqueous fatty phase -   800 Aqueous solid phase Page 5 

1-19. (canceled)
 20. A method for obtaining products of the food industry and/or feed industry from insects in a larval stage, the method comprising: a) killing the insects by heating, wherein uncrushed insects are mixed with water to kill the uncrushed insects, and wherein a temperature of the water in which the uncrushed insects are carried is greater than 60° C. during killing, and wherein a separation of the water occurs after the killing of the insects; b) comminuting the insects to form an insect pulp; c) shifting a pH-value of the insect pulp to an acidic range by adding an acid and malaxing the insect pulp for at least 45 minutes; and d) fractioning the insect pulp by centrifugal processing into at least two fractions, which include i) a solid phase and ii) a fatty phase, wherein the no additional enzymes are employed during the method.
 21. The method of claim 20, wherein the fractioning of the insect pulp is carried out in several stages.
 22. The method of claim 20, further comprising: drying the solid phase.
 23. The method of claim 20, wherein the addition of acid occurs within less than 5 minutes after the comminution.
 24. The method of claim 20, wherein the pH-value of the insect pulp after the addition of the acid is less than pH=6.5.
 25. The method of claim 20, wherein a temperature during malaxing or fractioning is at least 60° C.
 26. The method of claim 20, wherein the malaxing is performed for a period of 90-120 minutes.
 27. The method of claim 20, further comprising: processing the fatty phase obtained by fractioning using fat polishing.
 28. The method of claim 20, wherein an average particle size of insect parts in the insect pulp after the comminuting is between 1 and 2 mm.
 29. The method of claim 20, wherein the comminuting is carried out by shearing the insects in a meat grinder.
 30. The method of claim 20, wherein the acid is a diluted hydrochloric acid with a concentration of 0.001 mol/L to 0.5 mol/L.
 31. The method of claim 20, wherein after the fractioning the method further comprises: neutralizing at least one of the solid and fatty phases by adding a diluted NaOH solution.
 32. The method of claim 20, wherein after the killing of the insects and before the comminuting the insects, the insects are surface washed.
 33. The method of claim 20, wherein water is added during the malaxing or the fractioning.
 34. The method of claim 20, wherein the fractioning is carried out in a 3-phase decanter, a 2-phase decanter and a separator, or a 2-phase decanter.
 35. The method of claim 20, wherein the uncrushed insects are suspended in water to kill the uncrushed insects.
 36. The method of claim 20, wherein the killing is performed in a heat exchanger.
 37. The method of claim 20, wherein, during the killing of the uncrushed insects, the temperature of the water containing the uncrushed insects is 75-100° C.
 38. The method of claim 20, wherein the separation of the water after the killing of the uncrushed insects is performed by screening. 